/**
 * Copyright (C) 2012 Oleg Anastassov <o.anastasov@gmail.com>
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package kz.kstu.ent.app.delegate.factory;

import kz.kstu.ent.app.delegate.api.Delegate;

import java.util.HashMap;
import java.util.Map;

/**
 * @author Oleg Anastassov
 *         created: 4/16/12 5:43 PM
 */
public final class DelegateFactory {

    private static final String API_PACKAGE_NAME = "api";
    private static final String IMPL_PACKAGE_NAME = "impl";
    private static final String IMPL_CLASS_POSTFIX = "Impl";

    private static Map<Class<? extends Delegate>, Delegate> cache = new HashMap<Class<? extends Delegate>, Delegate>();

    private DelegateFactory() {
    }

    public static <T extends Delegate> T getDelegate(Class<T> delegateInterface) {
        if (cache.containsKey(delegateInterface)) {
            return (T) cache.get(delegateInterface);
        }
        try {
            String className = delegateInterface.getName().replace(API_PACKAGE_NAME, IMPL_PACKAGE_NAME) + IMPL_CLASS_POSTFIX;
            Class<T> delegateClass = (Class<T>) Class.forName(className);
            Delegate delegate = delegateClass.newInstance();
            cache.put(delegateClass, delegate);
            return (T) delegate;
        } catch (ClassNotFoundException e) {
            throw new IllegalArgumentException("Error during getting delegate: " + delegateInterface.getSimpleName(), e);
        } catch (InstantiationException e) {
            throw new IllegalArgumentException("Error during getting instance of delegate: " + delegateInterface.getSimpleName(), e);
        } catch (IllegalAccessException e) {
            throw new IllegalArgumentException("Error during getting instance of delegate: " + delegateInterface.getSimpleName(), e);
        }
    }
}
